This review may contain spoilers. I can handle the truth.
Not a real horror movie unless the black guy dies first (I guess). My theory is they killed each person with some justification in mind: the British couple and the academic weren't caucasian enough (also IP theft), the skinny kid urinated on the sacred tree, Christian was a cheatin' scoundrel commanded to ursine death by the May Queen.
Lost count of all the mind-altering drugs. Foreign substances messing with your mind, that's good horror material.
Reminds me of Rite of Spring, LDS rituals, The Wicker Man, Cabin in the Woods, Hereditary.